I doubt if they know what the names of the school subjects in which they study sciences mean.这句话怎么翻译?为什么是sciences

I doubt if they know what the names of the school subjects in which they study sciences mean.这句话怎么翻译?为什么是sciences 翻译一句英文谢谢 I doubt it.do you know what they cost? I doubt ___ David told us the truth,but they never doubt ___ David is honestA if;ifB if;thatC that;thatD that;if I doubt ___ David told us the truth,but they never doubt ___ David is honestA if;ifB if;thatC that;thatD that;if I doubt if they know what the names of the school subjects in which they study _____ mean.　　A.a science　　　 B.science　　　 C.sciences 　　　D.the science能帮我分析一下句子成分吗?还有为什么选C? i never doubt that… i doubt if/whether 都是什么意思阿i never doubt that…i doubt if/whether都是什么意思阿 I don‘t know if they ——(have)a party next week.是will have . i want to know if they(hold)____the spring sports meeting next month. I do not know if they would achieve in order to have the oath tomorrmw,don't,have,if,picnic,know,they,I,will,a(.) I really don't know if they ____ ____a party tomorrow.If they____I really don't know if they will have a party tomorrow.If they____(do还是have),I will call you. Well noted and thanks,will let you know if there is doubt(翻译成中文是什么意思?) I don't know if they will make anybody else's day ,but they made mine .啥意思 they heard i was good,they wanna see if its true.they know yer the one i wanna give it to.这歌的歌名什么 If they neglect their study,then it is no doubt putting the cart before the horse If I knew then what I know i doubt if i'll be living a very exciting life I don't know _____ they have passed the exam or notA.where B.if C.whether D.when